Effects of maternal subclinical hypothyroidism on obstetrical outcomes during early pregnancy

Background: Maternal hypothyroidism [overt hypothyroidism and subclinical hypothyroidism (SCH)] during early pregnancy is suspected to associate with adverse obstetrical outcomes. Aim: The aim of the present study was to investigate whether maternal SCH during the early stage of pregnancy increase obstetrical complications and whether treatment results in an improvement in these outcomes. Subjects and methods: A total of 756 women in the 1st trimester (≤12 weeks) of pregnancy were enrolled through 10 hospitals in Shenyang from 2007 to 2009. All participants underwent thyroid function testing in early pregnancy and their obstetrical outcomes were studied following delivery. Results: The incidence of spontaneous abortions in the SCH group was higher than the normal TSH group (15.48% vs 8.86%, p=0.03). No significant association was observed between SCH and other obstetrical complications including gestational hypertension, premature delivery, anemia, post-partum hemorrhage, low neonatal Apgar scores and low birth weight. Although levo-T4 (L-T4) treatment decreased the incidence of spontaneous abortions in women with SCH, it was not statistically significant when compared to women who did not receive treatment in the SCH group. None of the 28 women who received L-T4 treatment had premature delivery, low birth weight, hemorrhage, and low Apgar score. Conclusions: The incidence of spontaneous abortion in pregnant women with SCH increases in early pregnancy.